EP2S180F1020C4 Datasheet, PDF (450/768 Pages) Altera Corporation – Stratix II Device Handbook, Volume 1

Stratix II and Stratix II GX I/O Standards Support
Figure 4–10. Differential SSTL-2 Class I Termination
V_TT = 1.25 V V_TT = 1.25 V
Differential
Transmitter
25 Ω
50 Ω
Z0 = 50 Ω
50 Ω
Differential
Receiver
25 Ω
Z0 = 50 Ω
Figure 4–11. Differential SSTL-2 Class II Termination
VTT = 1.25 V VTT = 1.25 V
VTT = 1.25 V VTT = 1.25 V
Differential
Transmitter
50 Ω
25 Ω
50 Ω
50 Ω
Z0 = 50 Ω
50 Ω
Differential
Receiver
25 Ω
Z0 = 50 Ω
Differential SSTL-18 Class I and Differential SSTL-18 Class II
The 1.8-V differential SSTL-18 standard is formulated under JEDEC
Standard, JESD8-15: Stub Series Terminated Logic for 1.8-V (SSTL_18).
The differential SSTL-18 I/O standard is a 1.8-V standard used for
applications such as high-speed DDR2 SDRAM interfaces. This standard
supports differential signals in systems using the SSTL-18 standard and
supplements the SSTL-18 standard for differential clocks.
1 Stratix II and Stratix II GX devices support both input and
output levels operation.
4–12
Stratix II Device Handbook, Volume 2
Altera Corporation
January 2008